In a large number of therapeutic or diagnostic applications, it is necessary to implant a device such as a cannula for a long period in the body tissue. This is often necessary in order to for example enable therapeutic or diagnostic fluids to be administered repeatedly or for a long period. In doing so the problem occurs that the device must have a certain rigidity to enable puncturing and, on the other hand, it should be flexible in order to avoid injury when the patient moves.
Catheters are known from the documents US 20060100582 and US 20060100583 which are used to introduce a cannula into the body in order to for example administer drugs. In this case the catheter consists of a stiff or hard material for insertion into the body. The puncturing, pointed part of the catheter is removed after insertion into the body in order to avoid injury. The cannula can consist of a soft material so that it can adapt to movements.
The catheters of US 20060100582 and US 20060100583 have the disadvantage that the catheter is only used to puncture the body and does not have any further function after introduction into the body. Conversely, the cannula is not suitable for puncturing because it consists of a material whose shape adapts to the body and is not adapted to the forces of a puncture. Due to the invariable hardness of the catheter and the cannula, at least two elements are necessary to introduce a device into a body. One element for puncturing and a further element for the medical treatment.